Very interesting. Oddly, I’ve never really questioned the idea that being fat is unhealthy, probably because you hear it so much from medical authorities like doctors and public health officials. I can’t remember the last time I went to the doctor without being told to lose weight to improve health conditions I don’t even have (but am at, supposedly, higher risk for).
Let’s consider, though, why humans can become fat. The body stores energy in the form of fat for later conversion to sugars in the event of insufficient sugars to keep the body functioning. Sugar is only part of what the body needs to keep functioning (we also need amino acids we can’t synthesize except by deconstructing muscle, trace amounts of vitamins and minerals, and water), but it seems to be the most critical since our bodies are very good at storing it. To me this suggests that outright starvation is, evolutionarily speaking, a far greater threat than lack of access to particular essential comestibles. So our bodies are doing the right thing by making us fat because it protects us against the very real and serious threat of starvation.
The problem is that, today, in the first world, we have little risk of starvation. Even a lack of money is no reason to starve: charities and governments feed the destitute. But our bodies don’t know this, so they keep trying to put on fat. The result is that it’s very easy for people to become overweight because an ability to easily store and retrieve sugars in the form of fat was an evolutionary win: it doesn’t matter how fit you appear, if you don’t have enough fat you’ll be the first to die of starvation when there’s not enough food. So we should expect the majority of the population to be “overweight” whenever there is sufficient food available, which is exactly the trend we see (the time of real plenty has been, sadly, only in the last few decades).
So why is thin beautiful? Historically being thin was not attractive, especially for women, as evidenced by human art that has long shown women with at least some significant fat stores as the most attractive. In the first world, though, since sometime between about 1960 and 1980, thin became attractive. The reason seems clear: the middle class and even the poor could now get fat thanks to low cost high quality food, and so the rich (and others with high status) must have, probably mostly unconsciously, switched to thinking thin beautiful in order to retain a clear signal of higher status, a situation with plenty of precedent (consider the pale/tan swap, the car/horse swap, etc.). So regardless of health concerns, real or not, thin is in because it’s become a means of signaling status.
Given this, we should be highly suspicious of claims that we need to become thinner. It’s not a conspiracy, but it certainly looks like the usual game humans play to display status. Since our doctors are, unfortunately, also only human, they too are playing the status game and consider thin beautiful, and so are tempted to rationalize reasons why people should be thin since they want to help people and believe that they will be better if they lose weight. It’s a cruel twist that humans have a very hard time losing weight.
So, what’s to be done? Probably nothing, although it’s a worthy goal to push the elimination of weight as a status signal because even a partial success would result in a lot less suffering for billions of people. In the mean time, at least LW readers can eliminate from themselves false beliefs that anything but extreme obesity, or extreme skinniness, has anything more than a marginal health effect.
Let’s consider, though, why humans can become fat. The body stores energy in the form of fat for later conversion to sugars in the event of insufficient sugars to keep the body functioning.
You know that mammals cannot convert fat to sugar no matter what, right? (OK, there’s some limited evidence that glyoxylate cycle enzymes might be present in mammals, but even if they are active, what doesn’t seem terribly likely, the primary way to utilize fatty acids is definitely beta oxidation, which burns them for ATP).
To me this suggests that outright starvation is, evolutionarily speaking, a far greater threat than lack of access to particular essential comestibles.
There’s an argument that pre-agricultural food had a lot higher micronutrient to calorie ratio, so micronutrients were unlikely to be lacking even on very restricted diet. Modern food is supposedly selected for high calorie content.
Historically being thin was not attractive, especially for women, as evidenced by human art that has long shown women with at least some significant fat stores as the most attractive.
As far as I can tell most art shows women of healthy weight as attractive, very rarely overweight or obese kind.
Probably nothing, although it’s a worthy goal to push the elimination of weight as a status signal because even a partial success would result in a lot less suffering for billions of people.
Why would we want to eliminate a status signal that’s so easy to manipulate for smart people?
In the mean time, at least LW readers can eliminate from themselves false beliefs that anything but extreme obesity, or extreme skinniness, has anything more than a marginal health effect.
Metabolic syndrome seems real enough. Even if being moderately overweight wasn’t a health risk, it seems likely that someone moderately overweight is much more likely to become morbidly obese than someone with healthy weight. And far more people suffer from obesity-related diseases now than ever—so even if it’s mostly the extreme cases, if anti-fat interventions can get them to just moderately overweight it’s obviously worth it.
You know that mammals cannot convert fat to sugar no matter what, right? (OK, there’s some limited evidence that glyoxylate cycle enzymes might be present in mammals, but even if they are active, what doesn’t seem terribly likely, the primary way to utilize fatty acids is definitely beta oxidation, which burns them for ATP).
I was unaware of this. I am woefully ignorant of many aspects of biochemistry, so this was described as I recall the process being described. If fat isn’t converted back to sugars, I think it doesn’t affect the argument too much because the point is still to convert fat into energy later.
As far as I can tell most art shows women of healthy weight as attractive, very rarely overweight or obese kind.
I can’t find a handy reference, but I recall (from art history class) that women who were at least slightly overweight have long been portrayed as the ideal in art around the world. It may be necessary to consider that what’s considered a healthy weight today may have looked slightly overweight (indicating good access to quality food, a signal of status) to artists in the past.
Why would we want to eliminate a status signal that’s so easy to manipulate for smart people?
Because it’s not easy to manipulate no matter how smart you are. If someone were so smart as to figure out a successful, lasting intervention, they’d be rich from selling the diet to the rest of us. Taking a page from Robin Hanson, there’s a benefit to this similar to that of taxing the tall.
Because it’s not easy to manipulate no matter how smart you are.
Fat is trivial to manipulate. I lost 27kg (BMI 30 to 22) without any effort with ECA (with non-junk diet and a light amounts of exercise, nothing unusual), it’s stable for many years now. Just ask any bodybuilders for advice—they know how to do it, or read pubmed about ECA. The difficult part is not believing the popular culture’s completely ineffective methods, once you do that losing your fat is trivial matter.
While that may work for you, things like ECA have significant side effects for many people, especially those who have already developed weight-related illnesses, and there are some people for whom they don’t work. Given the effectiveness of the pharmaceutical industry in marketing medications, even non-prescription ones, the strong desires of millions of people to lose weight, and the length of time ECA products have been available, it seems unlikely that they are really as effective as you claim.
That’s a ridiculously strong version of efficient (medical) market hypothesis. As I said, ECA is semi-legal in States, and its marketing for weight loss is not allowed by FDA. Also, as a non-patented drug, medical industry has absolutely zero incentive to advertise it.
As far as anecdotes go, so far one person on lesswrong tried ECA, and got back to me saying it didn’t work. Turned out it was very low dosage ECA and on doubling it there were instant effects.
If you have weight problems, just go ahead, try it, and then tell me it didn’t work. That will be unlikely.
Let’s consider, though, why humans can become fat. The body stores energy in the form of fat for later conversion to sugars in the event of insufficient sugars to keep the body functioning. Sugar is only part of what the body needs to keep functioning (we also need amino acids we can’t synthesize except by deconstructing muscle, trace amounts of vitamins and minerals, and water), but it seems to be the most critical since our bodies are very good at storing it. To me this suggests that outright starvation is, evolutionarily speaking, a far greater threat than lack of access to particular essential comestibles. So our bodies are doing the right thing by making us fat because it protects us against the very real and serious threat of starvation.
That is the standard argument. Maybe it is true. But has it actually been tested? Is it observed that when famine strikes, the fat survive best, or that people with a tendency to fat in times of plenty survive better than the naturally thin in conditions of chronic scarcity? A lot of things with obvious explanations turn out not to be true, and there’s surely enough famine in the world to study.
After all, if the standard explanation is true, then we do know how people can make themselves thinner: eat as if food were in chronically short supply. This does not tell us how to make people thinner, short of concentration camp conditions, which certainly did work—none of the liberated prisoners were fat. But outside of such extremes, making people do anything is difficult.
See also Intermittent Fasting (eat only every other day), reputed to also extend life.
Being fat is unhealthy because it does leave you more susceptible to disease. The American health care system wastes billions of dollars each year on diseases and conditions that are a direct cause of obesity. Diabetes, heart disease, high blood pressure, and cardiovascular disease are just a few of the conditions that could be completely avoided by millions of Americans if they just ate/exercised better. It seems that easy access to high calorie junk food and absolutely no exercise (never taking the stairs) is just too much of a temptation for many people… and in evolutionary speak, is a good indicator of that person’s genes.
Obesity rarely occurs in nature because obese animals are targeted quickly by predators and quickly dispatched. The fat rabbit cannot escape the lean, muscular leopard chasing after it. In the event of a massive human starvation scenario I would argue that the fat people would be killed off first (possibly by the lean/muscular humans or predators) as the lean humans would require less resources and would be more capable of gathering food for the tribe. What good are obese/severely obese people in the hunter/gatherer world?
Think about all the benefits staying fit yields. It is easier to sit down, get up, row a boat, hunt for food, have sex, run, participate in sports, attract mates (good genes), defend your tribe, etc.
Obesity rarely occurs in nature because obese animals are targeted quickly by predators and quickly dispatched.
I would love to see evidence of this. I was under the impression that obesity is uncommon in the natural world because vast supplies of food are uncommon in the natural world.
Being fat is unhealthy because it does leave you more susceptible to disease.
That level of fat is not what I’m trying to address here. Many people are termed “fat” who are not so overweight as to actually correlate significantly with these diseases. I believe the data shows that exercise and genetic disposition, not weight, is more strongly correlated (sorry, no reference handy; feel free to prove me right or wrong on that). Many “fat” people are actually not at much of a health risk because they are in good shape, as you get at.
I would argue that the fat people would be killed off first
It depends on what kind of starvation scenario we’re talking about here. In the ancestral environment, starvation would typically be the result of changes in weather patterns. From what I understand, much of Africa during human evolution was temperate or subtropical forest with increasing amounts of savannah (the appearance of which it is often argued motivated the move to bipedalism). In a savannah seasonal changes drastically change the environment, such that in dry months there would be far fewer food resources than during wet months. Dry months don’t mean total starvation, but with fewer animals and fewer plants producing fruit or edible vegetative parts, the average daily caloric intake would have dropped. This is when fat reserves become important: fatten up in the wet months to help you make it through the dry months.
Total starvation scenarios don’t typically appear until the development of agriculture, because crop failure in an agricultural society often spells doom, especially if a monoculture provides the bulk of the sustenance. Such scenarios are a relatively recent occurrence, evolutionarily speaking, so we should expect to see only a slight selection effect as a result. In those cases, depending on the society, I can see how physical fitness may lead to survival (you out-compete your neighbors for the local food supplies, cf. post-apocalyptic survival scenarios), although the existence of a class of elites or strong cultural taboos might give greater advantage to those with other qualities.
What good are obese/severely obese people in the hunter/gatherer world?
None, but it’s a moot question because they don’t exist except perhaps in a hunter-gatherer society that is sufficiently large to require the emergence of strong hierarchical governance, thus allowing a few elites who no longer have to work to become fat. Just as with most animals, hunter-gatherers simply don’t have the opportunity to get fat.
The American health care system wastes billions of dollars each year on diseases and conditions that are a direct cause of obesity.
I assume you meant “a direct consequence of obesity”. Here’s a quote from the original interview that contradicts your claim:
Paul: The correlations between higher weight and greater health risk are weak except at statistical extremes. The extent to which those correlations are causal is poorly established. There is literally not a shred of evidence that turning fat people into thin people improves their health. And the reason there’s no evidence is that there’s no way to do it.
Now, if your point of view is informed, the right way forward in the argument would be producing citations.
Also, the part of your comment that deals with evolution seems confused to me. Hunter-gatherers don’t get obese because they don’t have access to cheap food, not because natural selection kills off obese people. If the latter were the case, modern people (who evolved from hunter-gatherers, after all) would have genetic safeguards against obesity.
Now, if your point of view is informed, the right way forward in the argument would be producing citations.
I am literally so baffled by the thesis presented above I can’t bring myself to disagree with it because I must be missing something. I mean, within five minutes on Google I found five studies showing strong correlations between various measures of body fat and coronary heart disease:
If I was willing to give it an hour, I’m sure I could have found sixty of them, and I know there are many similar studies about type II diabetes, cerebrovascular disease, et cetera. Because many of these are prospective studies, they have a better ability to show causality than longitudinal studies (although still not perfect). And another five minutes on Google find me several interventional studies about how turning fat people into thin people improves their health:
So what exactly is the thesis? That all of these studies are flawed in the same way? That there’s some vital causal step that’s been left out? Surely the author must know about these, right?
I think the story goes like this: there are correlations between weight and health. There are disputes, but let us skip that and assume for the sake of argument that thin people live longer than fat people. The next question is whether this is causal. If a fat person makes a big effort and becomes thin, will he have a long life, just like a person who was thin to begin with?
We can fill in the details of what the experiment looks like. We start with 200 fatties who want to get thin, and a random assignment of 100 to the control group, who get the usual crap advice about diet and exercise. Since this doesn’t work they remain fat. The others get special good advice about diet and exercise. They diet and exercise sucessfully and become thin. Then we wait.
Later (10 years? 20 years?) we follow up. Did the newly thin live longer? It is hard to be sure of the outcome in advance, the observed correlations do not guarantee it.
This is where Paul Campos jumps in a says “hey wait a minute, we cannot do that experiment because we do not have special good advice to hand out.”
Data from the scientific community indicate that a 15-wk diet or diet plus exercise program produces a weight loss of about 11 kg with a 60-80% maintenance after 1 yr. Although long-term follow-up data are meager, the data that do exist suggest almost complete relapse after 3-5 yr.
Think about planning the experiment that I sketched earlier. The key to getting a crisp, clear result is a ten or twenty year follow up measuring all-cause morbidity and mortality. The designer of the experiment needs to chose an intervention for the trial group, but the weight loss interventions that follow up five years later are reporting almost complete relapse for all interventions. So design of the experiment shudders to a halt.
There’s another, related explanation, which is superstimuli. A lot of modern processed food is developed to maximize its taste impact. If there’s a feedback between loop between good taste and higher consumption, widepsread and rising obesity may be the result of processed foods breaking this feedback by tasting too good. “Low-fat” may also exacerbate the problem, since fat helps signal satiety, so high-sugar, low-fat foods provide calories without curbing hunger much.
A genetic or evolutionary explanation seems unlikely because obesity is distributed non-randomly throughout society. It affects certain regions, subcultures, and classes very differently. This could be partly explained by the tendency (via affluence, culture, whatever) of certain groups to avoid eating highly processed high-calorie foods. It may be explained simply by net calorie consumption, but I’d be surprised if that itself is not correlated with the consumption of high-calorie processed foods.
It seems fairly obvious that you’re right about why humans become fat—i.e., because in our evolutionary past, it was adaptive to do so when there was a lot of food around—but I don’t see how you get from that point to “doctors are … playing the status game and consider thin beautiful” rather than “medical research has shown that obese people are at a higher risk from certain health problems”. It’s perfectly possible, and seems quite probable, that gaining weight is adaptive only a) up to a certain point, which was extremely rarely reached until recently, and/or b) under the actual conditions it was adaptive to—that is, when the weight is highly likely to come off again during a period of famine.
Perhaps I should have split this into two comments, then maybe it wouldn’t have gotten downvoted so far. Oh well, live and learn.
Yes, I agree that gaining weight is adaptive only up to a certain point, in part because in the ancestral environment there was not opportunity to get excessively fat. And I don’t deny that putting on extra weight is not really necessary in the first world. But having and maintaining a BMI in the “overweight” range does not appear to be dangerous and is arguably the body’s ideal state, since having less fat stores would be a real disadvantage.
I am probably guilty of making some too-big jumps in my reasoning to explain why fat is currently looked down on. I’m not entirely sure where they are, though, so if there’s any points in particular that need explanation let me know. Maybe we’ll find a flaw in my reasoning that I didn’t expect to be there in the details.
Very interesting. Oddly, I’ve never really questioned the idea that being fat is unhealthy, probably because you hear it so much from medical authorities like doctors and public health officials. I can’t remember the last time I went to the doctor without being told to lose weight to improve health conditions I don’t even have (but am at, supposedly, higher risk for).
Let’s consider, though, why humans can become fat. The body stores energy in the form of fat for later conversion to sugars in the event of insufficient sugars to keep the body functioning. Sugar is only part of what the body needs to keep functioning (we also need amino acids we can’t synthesize except by deconstructing muscle, trace amounts of vitamins and minerals, and water), but it seems to be the most critical since our bodies are very good at storing it. To me this suggests that outright starvation is, evolutionarily speaking, a far greater threat than lack of access to particular essential comestibles. So our bodies are doing the right thing by making us fat because it protects us against the very real and serious threat of starvation.
The problem is that, today, in the first world, we have little risk of starvation. Even a lack of money is no reason to starve: charities and governments feed the destitute. But our bodies don’t know this, so they keep trying to put on fat. The result is that it’s very easy for people to become overweight because an ability to easily store and retrieve sugars in the form of fat was an evolutionary win: it doesn’t matter how fit you appear, if you don’t have enough fat you’ll be the first to die of starvation when there’s not enough food. So we should expect the majority of the population to be “overweight” whenever there is sufficient food available, which is exactly the trend we see (the time of real plenty has been, sadly, only in the last few decades).
So why is thin beautiful? Historically being thin was not attractive, especially for women, as evidenced by human art that has long shown women with at least some significant fat stores as the most attractive. In the first world, though, since sometime between about 1960 and 1980, thin became attractive. The reason seems clear: the middle class and even the poor could now get fat thanks to low cost high quality food, and so the rich (and others with high status) must have, probably mostly unconsciously, switched to thinking thin beautiful in order to retain a clear signal of higher status, a situation with plenty of precedent (consider the pale/tan swap, the car/horse swap, etc.). So regardless of health concerns, real or not, thin is in because it’s become a means of signaling status.
Given this, we should be highly suspicious of claims that we need to become thinner. It’s not a conspiracy, but it certainly looks like the usual game humans play to display status. Since our doctors are, unfortunately, also only human, they too are playing the status game and consider thin beautiful, and so are tempted to rationalize reasons why people should be thin since they want to help people and believe that they will be better if they lose weight. It’s a cruel twist that humans have a very hard time losing weight.
So, what’s to be done? Probably nothing, although it’s a worthy goal to push the elimination of weight as a status signal because even a partial success would result in a lot less suffering for billions of people. In the mean time, at least LW readers can eliminate from themselves false beliefs that anything but extreme obesity, or extreme skinniness, has anything more than a marginal health effect.
You know that mammals cannot convert fat to sugar no matter what, right? (OK, there’s some limited evidence that glyoxylate cycle enzymes might be present in mammals, but even if they are active, what doesn’t seem terribly likely, the primary way to utilize fatty acids is definitely beta oxidation, which burns them for ATP).
There’s an argument that pre-agricultural food had a lot higher micronutrient to calorie ratio, so micronutrients were unlikely to be lacking even on very restricted diet. Modern food is supposedly selected for high calorie content.
As far as I can tell most art shows women of healthy weight as attractive, very rarely overweight or obese kind.
Why would we want to eliminate a status signal that’s so easy to manipulate for smart people?
Metabolic syndrome seems real enough. Even if being moderately overweight wasn’t a health risk, it seems likely that someone moderately overweight is much more likely to become morbidly obese than someone with healthy weight. And far more people suffer from obesity-related diseases now than ever—so even if it’s mostly the extreme cases, if anti-fat interventions can get them to just moderately overweight it’s obviously worth it.
I was unaware of this. I am woefully ignorant of many aspects of biochemistry, so this was described as I recall the process being described. If fat isn’t converted back to sugars, I think it doesn’t affect the argument too much because the point is still to convert fat into energy later.
I can’t find a handy reference, but I recall (from art history class) that women who were at least slightly overweight have long been portrayed as the ideal in art around the world. It may be necessary to consider that what’s considered a healthy weight today may have looked slightly overweight (indicating good access to quality food, a signal of status) to artists in the past.
Because it’s not easy to manipulate no matter how smart you are. If someone were so smart as to figure out a successful, lasting intervention, they’d be rich from selling the diet to the rest of us. Taking a page from Robin Hanson, there’s a benefit to this similar to that of taxing the tall.
Fat is trivial to manipulate. I lost 27kg (BMI 30 to 22) without any effort with ECA (with non-junk diet and a light amounts of exercise, nothing unusual), it’s stable for many years now. Just ask any bodybuilders for advice—they know how to do it, or read pubmed about ECA. The difficult part is not believing the popular culture’s completely ineffective methods, once you do that losing your fat is trivial matter.
While that may work for you, things like ECA have significant side effects for many people, especially those who have already developed weight-related illnesses, and there are some people for whom they don’t work. Given the effectiveness of the pharmaceutical industry in marketing medications, even non-prescription ones, the strong desires of millions of people to lose weight, and the length of time ECA products have been available, it seems unlikely that they are really as effective as you claim.
That’s a ridiculously strong version of efficient (medical) market hypothesis. As I said, ECA is semi-legal in States, and its marketing for weight loss is not allowed by FDA. Also, as a non-patented drug, medical industry has absolutely zero incentive to advertise it.
As far as anecdotes go, so far one person on lesswrong tried ECA, and got back to me saying it didn’t work. Turned out it was very low dosage ECA and on doubling it there were instant effects.
If you have weight problems, just go ahead, try it, and then tell me it didn’t work. That will be unlikely.
That is the standard argument. Maybe it is true. But has it actually been tested? Is it observed that when famine strikes, the fat survive best, or that people with a tendency to fat in times of plenty survive better than the naturally thin in conditions of chronic scarcity? A lot of things with obvious explanations turn out not to be true, and there’s surely enough famine in the world to study.
After all, if the standard explanation is true, then we do know how people can make themselves thinner: eat as if food were in chronically short supply. This does not tell us how to make people thinner, short of concentration camp conditions, which certainly did work—none of the liberated prisoners were fat. But outside of such extremes, making people do anything is difficult.
See also Intermittent Fasting (eat only every other day), reputed to also extend life.
Being fat is unhealthy because it does leave you more susceptible to disease. The American health care system wastes billions of dollars each year on diseases and conditions that are a direct cause of obesity. Diabetes, heart disease, high blood pressure, and cardiovascular disease are just a few of the conditions that could be completely avoided by millions of Americans if they just ate/exercised better. It seems that easy access to high calorie junk food and absolutely no exercise (never taking the stairs) is just too much of a temptation for many people… and in evolutionary speak, is a good indicator of that person’s genes.
Obesity rarely occurs in nature because obese animals are targeted quickly by predators and quickly dispatched. The fat rabbit cannot escape the lean, muscular leopard chasing after it. In the event of a massive human starvation scenario I would argue that the fat people would be killed off first (possibly by the lean/muscular humans or predators) as the lean humans would require less resources and would be more capable of gathering food for the tribe. What good are obese/severely obese people in the hunter/gatherer world?
Think about all the benefits staying fit yields. It is easier to sit down, get up, row a boat, hunt for food, have sex, run, participate in sports, attract mates (good genes), defend your tribe, etc.
I would love to see evidence of this. I was under the impression that obesity is uncommon in the natural world because vast supplies of food are uncommon in the natural world.
That level of fat is not what I’m trying to address here. Many people are termed “fat” who are not so overweight as to actually correlate significantly with these diseases. I believe the data shows that exercise and genetic disposition, not weight, is more strongly correlated (sorry, no reference handy; feel free to prove me right or wrong on that). Many “fat” people are actually not at much of a health risk because they are in good shape, as you get at.
It depends on what kind of starvation scenario we’re talking about here. In the ancestral environment, starvation would typically be the result of changes in weather patterns. From what I understand, much of Africa during human evolution was temperate or subtropical forest with increasing amounts of savannah (the appearance of which it is often argued motivated the move to bipedalism). In a savannah seasonal changes drastically change the environment, such that in dry months there would be far fewer food resources than during wet months. Dry months don’t mean total starvation, but with fewer animals and fewer plants producing fruit or edible vegetative parts, the average daily caloric intake would have dropped. This is when fat reserves become important: fatten up in the wet months to help you make it through the dry months.
Total starvation scenarios don’t typically appear until the development of agriculture, because crop failure in an agricultural society often spells doom, especially if a monoculture provides the bulk of the sustenance. Such scenarios are a relatively recent occurrence, evolutionarily speaking, so we should expect to see only a slight selection effect as a result. In those cases, depending on the society, I can see how physical fitness may lead to survival (you out-compete your neighbors for the local food supplies, cf. post-apocalyptic survival scenarios), although the existence of a class of elites or strong cultural taboos might give greater advantage to those with other qualities.
None, but it’s a moot question because they don’t exist except perhaps in a hunter-gatherer society that is sufficiently large to require the emergence of strong hierarchical governance, thus allowing a few elites who no longer have to work to become fat. Just as with most animals, hunter-gatherers simply don’t have the opportunity to get fat.
I assume you meant “a direct consequence of obesity”. Here’s a quote from the original interview that contradicts your claim:
Now, if your point of view is informed, the right way forward in the argument would be producing citations.
Also, the part of your comment that deals with evolution seems confused to me. Hunter-gatherers don’t get obese because they don’t have access to cheap food, not because natural selection kills off obese people. If the latter were the case, modern people (who evolved from hunter-gatherers, after all) would have genetic safeguards against obesity.
I am literally so baffled by the thesis presented above I can’t bring myself to disagree with it because I must be missing something. I mean, within five minutes on Google I found five studies showing strong correlations between various measures of body fat and coronary heart disease:
In a 14-year prospective study, middle-aged women with a BMI >23 but 25 but <29 had a 72% increased risk
When participants with the highest waist-to-hip ratio were compared with those having the lowest ratio, there was an 80 percent increase in risk.
The risk of any CHD event, a nonfatal event, and a fatal event among adults was positively associated with BMI at 7 to 13 years of age for boys and 10 to 13 years of age for girls.
These prospective cohort studies employed simple indices of body-fat distribution such as waist-to-hip circumference ratio or subscapular skinfold. Their similar results suggested that increased abdominal obesity conferred a two-fold increased risk of ischemic heart disease among middle-aged men.
IAF and trunk fat were consistently positively related to CVD risk factors, whereas leg fat was consistently negatively related to CVD risk, indicating that IAF and trunk fat may put women at increased risk of developing CVD.
If I was willing to give it an hour, I’m sure I could have found sixty of them, and I know there are many similar studies about type II diabetes, cerebrovascular disease, et cetera. Because many of these are prospective studies, they have a better ability to show causality than longitudinal studies (although still not perfect). And another five minutes on Google find me several interventional studies about how turning fat people into thin people improves their health:
Our study has shown that weight loss of as little as 6.5 percent in individuals with [metabolic syndrome] results in substantial reductions in blood pressure, glucose, triglycerides and total cholesterol, all factors that lead to heart disease,’ MDBHVC director Christie Ballantyne said. These impressive results occur early in the weight loss, well before individuals even begin to approach their ideal body weight,’ Ballantyne said.
Weight loss was significantly associated with lower rate of the composite outcome after adjustment for age, sex, smoking, dyslipidemia, diabetes, hypertension, myocardial infarction, and obese status [hazard ratio (HR)=0.62; P=0.018]. Subgroup analysis showed that patients who lost weight had favorable outcomes both in patients with BMI <25 (HR=0.32; P=0.035) and those with BMI ≥25kg/m2 HR=0.64; P=0.032.
So what exactly is the thesis? That all of these studies are flawed in the same way? That there’s some vital causal step that’s been left out? Surely the author must know about these, right?
I think the story goes like this: there are correlations between weight and health. There are disputes, but let us skip that and assume for the sake of argument that thin people live longer than fat people. The next question is whether this is causal. If a fat person makes a big effort and becomes thin, will he have a long life, just like a person who was thin to begin with?
We can fill in the details of what the experiment looks like. We start with 200 fatties who want to get thin, and a random assignment of 100 to the control group, who get the usual crap advice about diet and exercise. Since this doesn’t work they remain fat. The others get special good advice about diet and exercise. They diet and exercise sucessfully and become thin. Then we wait.
Later (10 years? 20 years?) we follow up. Did the newly thin live longer? It is hard to be sure of the outcome in advance, the observed correlations do not guarantee it.
This is where Paul Campos jumps in a says “hey wait a minute, we cannot do that experiment because we do not have special good advice to hand out.”
That is a controversial position, and the key issue seems to be the duration of follow up. Qutoing from How effective are traditional dietary and exercise interventions for weight loss?
Think about planning the experiment that I sketched earlier. The key to getting a crisp, clear result is a ten or twenty year follow up measuring all-cause morbidity and mortality. The designer of the experiment needs to chose an intervention for the trial group, but the weight loss interventions that follow up five years later are reporting almost complete relapse for all interventions. So design of the experiment shudders to a halt.
There’s another, related explanation, which is superstimuli. A lot of modern processed food is developed to maximize its taste impact. If there’s a feedback between loop between good taste and higher consumption, widepsread and rising obesity may be the result of processed foods breaking this feedback by tasting too good. “Low-fat” may also exacerbate the problem, since fat helps signal satiety, so high-sugar, low-fat foods provide calories without curbing hunger much.
A genetic or evolutionary explanation seems unlikely because obesity is distributed non-randomly throughout society. It affects certain regions, subcultures, and classes very differently. This could be partly explained by the tendency (via affluence, culture, whatever) of certain groups to avoid eating highly processed high-calorie foods. It may be explained simply by net calorie consumption, but I’d be surprised if that itself is not correlated with the consumption of high-calorie processed foods.
It seems fairly obvious that you’re right about why humans become fat—i.e., because in our evolutionary past, it was adaptive to do so when there was a lot of food around—but I don’t see how you get from that point to “doctors are … playing the status game and consider thin beautiful” rather than “medical research has shown that obese people are at a higher risk from certain health problems”. It’s perfectly possible, and seems quite probable, that gaining weight is adaptive only a) up to a certain point, which was extremely rarely reached until recently, and/or b) under the actual conditions it was adaptive to—that is, when the weight is highly likely to come off again during a period of famine.
Perhaps I should have split this into two comments, then maybe it wouldn’t have gotten downvoted so far. Oh well, live and learn.
Yes, I agree that gaining weight is adaptive only up to a certain point, in part because in the ancestral environment there was not opportunity to get excessively fat. And I don’t deny that putting on extra weight is not really necessary in the first world. But having and maintaining a BMI in the “overweight” range does not appear to be dangerous and is arguably the body’s ideal state, since having less fat stores would be a real disadvantage.
I am probably guilty of making some too-big jumps in my reasoning to explain why fat is currently looked down on. I’m not entirely sure where they are, though, so if there’s any points in particular that need explanation let me know. Maybe we’ll find a flaw in my reasoning that I didn’t expect to be there in the details.